The present invention relates to semiconductor device fabrication and integrated circuits and, more specifically, to methods for forming a vertical-transport field-effect transistor and structures for a vertical-transport field-effect transistor.
Device structures for a field-effect transistor generally include a body region, a source and a drain defined in the body region, and a gate electrode configured to switch carrier flow in a channel formed in the body region. When a control voltage exceeding a designated threshold voltage is applied to the gate electrode, carrier flow occurs in an inversion or depletion layer in the channel between the source and drain to produce a device output current. The body region and channel of a planar field-effect transistor are located beneath the top surface of a substrate on which the gate electrode is supported.
Planar field-effect transistors and fin-type field-effect transistors constitute a general category of transistor structures in which the direction of gated current in the channel is in a horizontal direction parallel to the substrate surface. In a vertical-transport field-effect transistor, the source and the drain are arranged at the top and bottom of a semiconductor fin or pillar. The direction of the gated current transport in the channel between the source and drain is generally perpendicular (i.e., vertical) to the substrate surface and, therefore, parallel to the height of the semiconductor fin or pillar.